The present invention relates to a liquid level controller, and particularly to a liquid level controller that can completely draw liquid out of a liquid tank and avoid the incorrect actions caused by the impurity within the liquid to choke the liquid level controller.
Various liquid level controllers are known and widely used for sucking liquid. These liquid level controller commonly use mercury switches or electrode sensors to control the liquid level.
The mercury switches include a lever with a floating ball at the end thereof. The floating ball locates on a liquid surface and is supported by the buoyancy of the liquid. The lever only oscillates in a small and fixed region so it can't draw the liquid under the floating ball, also the floating ball device will damage easily and lose its functions, and the floating ball mechanism must be located under the liquid surface, therefore the installation, maintenance and fixing of the liquid level controller are more difficult.
The electrode sensors include a high level electrode sensor and a low level electrode sensor for detecting the high and low levels of the liquid. The electrode sensors must locate under the liquid surface therefore the installation, maintenance and fixing are more difficult. Furthermore, the electrode sensors are easily corroded by tile electric current or eroded by the impurity of the liquid to make the electrode sensors damage and lose its functions.